Improvement in coating metals with tin



IUNITED STATES PATENT OFFICE.

CARL VVINZEN, OF ALBANY, NEW YORK.

IMPROVEMENT IN COATING METALS WITH TIN.

Specification forming part of Letters Patent No. 22,995, dated February 15, 1859.

To all whom it may concern Be it known that I, CARL WINZEN, of the city of Albany, in the State of New York, have invented a new and useful Method of Coating Metals \Vith Tin, usually denominated Tinning; and I do hereby declare that the following is a full and exact description of the process which constitutes my said invention.

To twenty pounds of water add three ounces of sulphuric acid. Stir the mixture well, and then add four ounces of salt of tin. Dissolve two ounces of alum in a sufiicient quantity of tepid water,and add this solution to the abovedescribed mixture. Then take a piece of spelter of any convenient size and connect-it with the metal to be tinned, either by direct contact, or, which is preferable, by means of an iron wire of suitable length and fleure. After the lapse of five minutes remove the metal from the fluid and scour it with sand, using for this purpose a stiff brush, piece of woolen cloth, or other convenient thing adapted to the purpose. Then again immerse the metal and spelter, as before directed. At the expiration of fifteen minutes again remove the metal,

- dry it with sawdust, and again scour itin like manner with dry sand until it appears bright and smooth. It a coating of extraordinary thickness is required, continue the second immersion for a longer time, proportioned to the thickness desired.

When this process is to be applied to culinary or other vessels, the inner surface of which only is required to be tinned, it will be sufficient, instead of immersing the vessel, to fill it with the fluid. This method, it will be seen, dispenses with all previous preparation of the surface of the'metal to be tinned by cleansing, a tedious process, which, especially in thetinning of cast-iron, has been hitherto foundindispensable. It dispenses, also,it will be observed, with the use of heat and of an exterior galvanic battery. Bythis method the tin becomes much more firmly and durably united with the surface to which it is to be applied and resists heat far better than by any method hitherto used. It also effectually resistsheat, as it also does all tendency in the metal to oxidize or corrode, and when applied to culinary vessels is therefore in no way injurious to health, It may be applied with equalfacility and success to cast-iron,wrought-iron,copper, brass, or lead. Besides the great saving of time by this method and its superiority, as above stated, over the accustomed modes of tinning in other respects, it saves, also, it is believed, more than half the expense attending the process of tinningheretofore in use.

The quantities and proportions of the ingredients employed, as above stated, I have found to he apparently, and I believe themto be, the best adapted to the purpose; but it may be that they admit of slight variations without materially impairing their efficacy or at all interfering with the principle and essential nature of my invention.

My invention may be summarily described as a new, cheap, and expeditious mode of depositing tin from a cold solution upon the surface of other metals, whereby a firm and durable adhesion thereto is secured.

Having carefully examined the other modes of tinning-and especially Roseleurs, as being somewhat in advance of the other modes hitherto known-I have found that by none of them can the process of tinning be performed in a manner so thorough, durable, and cheap as by mine, asuperiority easily demonstratable by experiment, Tinning by means ot'bitartrate of potash, as recommended by ltoseleur, has neverbeenconsidered of much value, being neither th orough nor durable, and not to he accomplished at all without a heat of at least 80 or 90. The superiority of my method inpoint of simplicity and celerity is equally conspicuous. For example, Roseleurs process can never be rendered etiective without a very hot bath, nor can it be successfully applied without previously soaking the metal to be tinned, especially if it be cast-iron, while in mine no heat is required, and the processes of cleansing and tinning are performed at one and the same time, and Roseleurs process re'quires at least two hours, while mine requires no more than about twenty minutes for its completion. With regard to the merit claimed by Roseleur on account of the simultaneous applicability of his process to different metals, itis obvious that this is equally true of mine by means of connecting-wires. Alltheingredients of which my solution is composed, or their, equivalents are used by Roseleur with the exception of sulphuric acid, and with that exception, therefore, I claim no exclusive right to their employment in the process of tinning; butI have found sulphuric acid to exert a most important agency, first, in cleansing the metal to bev tinned; second, in promoting thorough crystallization; and, third, in accelerating the whole process. Galvanic action has also long been put in requisition in the process of tinning, and I therefore claim no exclusive right to its use for this purpose; but the mode I have adopted of rendering it effective by means of a connecting-Wire I believe to be new, and I know it to be on several accounts preferable to any other mode hitherto employed. The method adopted by Roseleur of immersing pieces of zinc in the solution along with the metals to be tinned is "ery objectionable. He states truly that the quantity of zinc to be used must be proportioned to the extent of the surface to be covered; but he gives no information by which the proportion can be ascertained, nor do I believe it to be possible by his method to obtain a satisfactory result, and I abstain from here making a formal claim to the connecting-wire for the purpose of having it embraced in my patent only because it might be supposed by others not to be patentable,'an(l thus lead to controversy.

What I claim, therefore, as my invention, and desire to secure by Letters Patent, subject to the foregoing explanations and disclaimers, 1s-

Ihe solution composed of the ingredients in substantially the same proportions applied to accomplish the process of tiuning, and used substantially in the manner above described.

CARL WINZEN.

Witnesses WM. ROIIIAGKER, ROBERT COURTNEY. 

